Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on a targeted system.
The vulnerability is due to improper handling of malformed H.323 packets by the affected software. An unauthenticated, remote attacker could exploit this vulnerability by sending malformed H.323 packets to a targeted device. If successful, the attacker could cause the device to reload or trigger memory leaks that may result in system instabilities, resulting in a DoS condition.
Cisco has confirmed the vulnerability in a security advisory and released software updates.
Indicators of Compromise
Cisco has published a list of affected Cisco IOS Software releases in the security advisory. The Vendor Announcements section of this alert contains a link to the advisory.
The vulnerability is due to improper processing of transit, malformed H.323 packets by the affected software when the zone-based firewall is configured to perform H.323 traffic inspection.
An unauthenticated, remote attacker could exploit this vulnerability by sending malformed H.323 packets to a targeted device. When processed, the packets could cause the device to reload. Exploitation could result in a DoS condition.
To exploit the vulnerability, the attacker may provide a multimedia file to the user and persuade the user to open or execute the file by using misleading language or instructions. Opening the file may result in the processing of malformed H.323 packets by the affected software.
Cisco indicates through the CVSS score that functional exploit code exists; however, the code is not known to be publicly available.
Administrators are advised to apply the appropriate updates.
Administrators may consider using IP-based access control lists (ACLs) to allow only trusted systems to access the affected systems.
Administrators are advised to monitor affected systems.
Cisco customers with active contracts can obtain updates through the Software Center at the following link: Cisco. Cisco customers without contracts can obtain upgrades by contacting the Cisco Technical Assistance Center at 1-800-553-2447 or 1-408-526-7209 or via e-mail at firstname.lastname@example.org.
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Cisco Multivendor Vulnerability Alerts respond to vulnerabilities identified in third-party vendors' products. These alerts contain information compiled from diverse sources and provide comprehensive technical descriptions, objective analytical assessments, workarounds and practical safeguards, and links to vendor advisories and patches.